Several weeks ago, I ran a series of posts wherein I discussed a possible way of gleaning information from the YourMorals database that attempts to clean out the selection bias and give us some estimate of the geographic distribution of the moral foundations in the United States. This method tries to correct for some of the biggest problems in a self-selected sample (recently highlighted by Ravi Iyer, here).
One way to check the validity of these measures is to apply them to real world data. The recent 2010 midterm elections provide an excellent opportunity to do this.
The Guardian generously posted a downloadable version of the 2010 midterm election results on their website. For the following analyses, I will use the estimated moral foundation score for each congressional district derived from the YourMorals data.
The first thing to examine is the simple bivariate relationship between the Republican share of the vote in 2010 and each of the moral foundations.* The figure below displays these relationships. On the y-axis we have the percent of the vote won by the Republican candidate, and on the x-axis we have the estimated moral foundation score of the congressional district. In the upper-right corner, I’ve displayed the simple correlation coefficient between the two variables, and the thick red line shows the best linear fit.
This figure looks very similar to one I posted earlier detailing the relationship between the vote for Obama in the 2008 elections and the moral foundations. Indeed given the strong autocorrelation from year to year in election results, this is no real surprise.
The most important changes in election results from year to year tend to be the across-the-board shifts toward one party or the other (for more on this general trend, see Eric McGhee’s cogent analysis at the Monkey Cage).
To what extent can the moral foundations data explain this shift? After some exploration of the raw data, it became clear that the area to focus on was the seats held by Democrats. For the remaining analysis, I’ll restrict the data to the 257 seats that the Democrats held prior to the 2010 elections. For the dependent variable, I will use the difference between the vote for John McCain in 2008 in a particular district and the vote for the Republican House candidate.
Overall, among seats held by the Democratic Party, there was a two-point shift in the vote toward the Republicans. The figure below shows the distribution of this shift over the partisan voting index (PVI) of the district (the PVI is the average deviation of the district from the national presidential vote in the last three elections—for example, a district with a PVI of -10 votes ten points more Democratic on average than the average vote in the country).
Districts that fell on the left side of the figure (those with large negative values of the PVI), were generally safe Democratic seats. Those that are located toward the center and the right, were in more danger. We can see that the shifts were greatest near in these most marginal seats.
To examine the possible explanations of this shift, I looked at how the relationship between the PVI and the shift in the Republican vote in 2010 changed based the moral foundations. I divided all of the districts into two categories for each of the moral foundations. Those that were above the median score on a foundation were labeled as “high” on that particular foundation and the remaining were labeled “low.” The figure below shows the how the relationship between a district’s PVI score and the shift toward the Republican party changed when we break the data down further into these different foundations. The dashed lines show the relationship in districts that scored above the median on a particular foundations, and the solid lines show those that scored below the median.
There are several interesting patterns to note here. First, there did not seem to be any differential effects in the safest Democratic districts. At a PVI of -15, the data show the general shift toward the Republican Party discussed above (about 2 points more Republican). However, as we move toward the right-hand side of the PVI scale, toward the marginal seats and those that actually go for Republicans in their presidential voting, the gap between the high and low scoring foundations is largest. Most interestingly, it is those districts that scored highest on the liberal foundations (Harm and Fairness) that showed the biggest shift toward the Republicans in 2010. None of these relationships hold up in districts held by the Republican Party. It is something unique to the campaign against incumbent Democrats.
Finally, no discussion of the 2010 midterms would be complete without some mention of the Tea Party. The New York Times compiled a list of all of the Tea Party candidates (see here) in the 2010 elections. Of the 129 candidates that the Times identified, 120 of them ran in districts that the Democrats held in 2008. This represents almost 47% of all the races in districts where the Democrats had control in 2008.
What explains the emergence of Tea Party candidates in general elections?** The figure below shows how the probability of seeing a Tea Party challenger increases over the PVI (again, analysis was restricted to only those 257 seats that were held by Democrats in 2008). As we would expect, the probability increases as we move toward the more competitive districts.***
The most powerful relationship was seen in the districts that scored above the median on the Fairness foundation. Districts that scored high on the Fairness foundation and were competitive had a much greater probability of seeing a Tea Party challenger than those others. Smaller relationships were seen for the other foundations. Interestingly, the foundations did not seem to affect how well the Tea Party candidates did once in the race, only their probability of entering.
* In all of these analyses it is important to keep a few things in mind. First, the district level foundation scores were computed based on the entire voting age population of each congressional district. A big part of the story in 2010 was the “enthusiasm gap” between Democrats and Republicans. These analyses do not make adjustments for the differential turnout. Second (and this is somewhat related to the first point), the district level estimates for the moral foundations are aggregate measures. It would be inappropriate to infer individual level behavior from these district level statistics (this is known as the “ecological inference fallacy”).
** It would probably be most appropriate to examine the emergence and success of Tea Party candidates in Republican primaries. If we had a good measure of the moral foundations of Republican primary voters in 2010, this would make a fascinating analysis. However, we only have a measure of the district’s score on the moral foundations as a whole. At present, it is not possible to break this out by party.
*** The plots show predicted probabilities from similarly specified logistic regressions. The regression equation took the form,
Logit(P(Tea Party Challenger) )= a + b(1)*PVI + b(2)*High Foundation + b(3)*PVI*Foundation